Saudi Crown Prince Mohammed bin Salman, the country's presumptive heir, has been attempting to portray himself as a reformer working to modernize and liberalize the country. Khashoggi's media appearances often flew in the face of that image.

Appearing on Al Jazeera, Kashoggi said, "I still see him as a reformer, but he is gathering all power within his hand."

And he told RT, "It is reason to worry, and I put it this way: he is doing the right things the wrong way."

Khashoggi's most trenchant criticisms came from his opinion pieces in The Washington Post, where he accused Salman of imposing "very selective justice," creating a "climate of fear and intimidation," and behaving like Russia's authoritarian president Vladimir Putin.

Khashoggi last spoke in public during a Middle East Monitor conference in London about the Israeli-Palestinian conflict. He entered the Saudi consulate and went missing days later.